Mixed-mode (I/II) interlaminar fracture of glued-laminated timber

Publication date: 5 October 2017
Source:Materials & Design, Volume 131
Author(s): Yanhua Zhao, Zheng Li, Bohan Xu
Mixed-mode bending (MMB) tests, together with double cantilever beam (DCB) and end-notched flexure (ENF) tests were conducted on Mongolian Scots pine to investigate the initial interlaminar fracture toughness of glued-laminated timber (glulam) under various mixed mode I/II conditions. By changing the loading lever location, a wide range of apparent ratios between mode I and mode II fracture were covered for MMB tests. Using the recorded critical load, interlaminar fracture toughness in terms of energy release rate was determined using compliance combination method (CCM), where the influence of growth ring orientations of adjacent laminae of glulam was highlighted. The results reveal the initial interlaminar fracture toughness was influenced by the growth ring orientation when mode II fracture component is larger. And an empirical power criterion was proven to be applicable to the mixed mode I/II interlaminar fracture toughness envelope of glulam.

Graphical abstract

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